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Updated: Jun 2, 2026
Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
[MecA and pvl genes detection in Staphylococcus aureus strains isolated from lower respiratory tract infections]
E Năstase1, Olivia Dorneanu, Teodora Vremeră
1Facultatea de Medicină, Disciplina de Boli Infecţioase, Universitatea de Medicină si Farmacie Gr.T. Popa Iaşi.
Unlabelled:
Although community-acquired Staphylococcus aureus pneumonia with highly virulent Panton-Valentine leukocidin (PVL)-positive strains, a severe disease with significant lethality, is rare, especially in adult and adolescent patients, recent reports highlight that these infections are on the rise. On the other hand, methicillin-resistant S. aureus (MRSA) is one of the high-risk and potential multi-drug resistant microorganisms.
Objectives:
The aim of this study was to investigate the prevalence of mecA and pvl genes in S. aureus strains isolated from lower respiratory tract infections and to assess the antibiotic resistance profile of these strains.
Material And Method:
The antibiotic susceptibility testing was performed by the disk diffusion method according to CLSI recommendations in 32 consecutive non-repeated S. aureus strains isolated from sputum specimens and endotracheal aspirates of hospitalized patients over the period from January 2005 to December 2009. Only 20 strains (2008-2009) were tested for the presence of mecA and pvl genes by real-time PCR and detection with specific fluorescence probes.
Results:
Of the 32 S. aureus isolates, 68.7% were MRSA. MRSA strains showed higher resistance rates to gentamicin, tetracycline, rifampicin, fluoroquinolones comparing to the methicillin susceptible ones. Only one strain produced pvl; it was isolated from a 7 year old child with lethal sepsis with pulmonary and meningeal secondary localisations.
Conclusions:
Glicopeptides and linezolid are therapeutic options indicated in the treatment of staphylococcal pneumonia produced either by MRSA strains or pvl positive S. aureus strains.
Insights
Community-acquired Staphylococcus aureus pneumonia is rising, with methicillin-resistant S. aureus (MRSA) posing a significant threat. This study found a high prevalence of MRSA and identified key antibiotic resistance patterns in lower respiratory tract infections.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Community-acquired Staphylococcus aureus pneumonia, particularly with Panton-Valentine leukocidin (PVL)-positive strains, is a severe and increasingly reported condition.
- Methicillin-resistant S. aureus (MRSA) represents a significant public health concern due to its high-risk nature and potential for multi-drug resistance.
Purpose of the Study:
- To determine the prevalence of mecA and pvl genes in S. aureus strains from lower respiratory tract infections.
- To analyze the antibiotic resistance profiles of these S. aureus isolates.
Main Methods:
- Antibiotic susceptibility testing using the disk diffusion method on 32 S. aureus strains isolated from sputum and endotracheal aspirates.
- Real-time PCR with specific fluorescence probes to detect mecA and pvl genes in 20 strains.
Main Results:
- 68.7% of the 32 S. aureus isolates were identified as MRSA.
- MRSA strains exhibited higher resistance rates to gentamicin, tetracycline, rifampicin, and fluoroquinolones compared to methicillin-susceptible strains.
- A single PVL-positive strain was identified in a fatal case of sepsis in a 7-year-old child.
Conclusions:
- Glicopeptides and linezolid are recommended therapeutic options for staphylococcal pneumonia caused by MRSA or PVL-positive S. aureus strains.
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